Today in the field of roll fed carton packaging systems for liquid food products, e.g. Tetra Brik™ systems sold and marketed by Tetra Pak™, it is known to use a sealing apparatus provided with convex portions in order to control a volume of product in a lower part of a tube of packaging material during a transversal sealing stage. In this way it is possible to assure that a package being formed contains a volume according to set requirements.
The convex portions can be provided at different places of the sealing apparatus, such as the sealing members. More particularly, the convex portions of the sealing members can be placed on sections of the sealing members placed next to sealing surfaces of the sealing members. By having convex portions placed in this way, the convex portions will during the sealing stage provide for that a top panel and a bottom panel, respectively, of the package being formed are pushed inwards, towards a mid-portion of the tube, and thereby a more controlled forming of the package can be achieved.
The general principle as well as an example of how convex portions can be used in roll-fed carton packaging systems are presented in EP 1 509 453 by the applicant, Tetra Laval Holdings & Finance S.A.
The prior art successfully achieves to present a packaging system that is reducing a problem of having packages produced with an inconsistent volume content. However, having the convex portions set correctly may be a cumbersome and lengthy process. There are a number of factors to take into account, such as product properties and packaging material properties, and if the packaging system is used for a variety of different products and types of packaging material the process may be needed to be repeated often.